The present disclosure relates generally to turbine assemblies and, more particularly, to systems and methods of film cooling hot gas path components formed from ceramic material.
Rotary machines, such as gas turbines, are often used to generate power with electric generators. Gas turbines, for example, have a gas path that typically includes, in serial-flow relationship, an air intake, a compressor, a combustor, a turbine, and a gas outlet. Compressor and turbine sections include at least one row of circumferentially-spaced rotating buckets or blades coupled within a housing. At least some known turbine engines are used in cogeneration facilities and power plants. Engines used in such applications may have high specific work and power per unit mass flow requirements. To increase operating efficiency, at least some known gas turbines may operate at increased temperatures.
At least some known hot gas path components in gas turbines are formed from ceramic material, which is generally capable of withstanding greater temperatures than metallic material. For example, ceramic matrix composites (CMCs) commonly include continuous fibers of silicon carbide embedded within a matrix material. Although CMC components offer higher temperature capability than metallic counterparts, CMC components are sometimes limited by environmental factors in which the CMC components operate. For example, in the presence of oxygen and water vapor, silicon carbide forms carbon dioxide and silicon hydroxide. The silicon hydroxide can cause recession and reduce the service life of the CMC components.